Tablets are position acurate, wher mice just wobble a little ball and push the cursor more-or-less in the direction you want to go. The spot on the tablet will match a spot on the screen every time. Tablets were originally for CAD, but they work well in PhotoShop (even better in Fractal Paint though), all modern ones are pressure sensitive, - as you push "in" you gat another control, typically set to brush width. I have one of the original Wacom 6 x 9" tablets they used to bundled with Fractal Paint (version 2, BTW, so it's pretty old), I still use it all the time in Photoshop. You need the tablet do the computer knows where the pen is- the pen is just a hunk of plastice with a magnet (oe something!) and a spring.